The sonographer applies gel on the part of the body which, needs an ultrasound image. The gel prevents air blocking, which can block the sound waves that create the images. Rubbing the transducer on the area under observation produces images on the computer. The device collects the sound waves and bounces back, sending them to the computer and generating ultrasound images.

Sometimes there arises the insert transducer into the body. Transesophageal echocardiogram needs inducing transducer into the oesophagus to obtain heart images. A transrectal ultrasound needs to insert a transducer through the rectum to get scan images of the prostate. Transvaginal ultrasound involves inserting the instrument into the vagina to scan the uterus and ovaries.